Patent Document 1, for example, discloses a conventional variable displacement swash plate type piston pump. The piston pump is capable of changing displacement of hydraulic oil (hydraulic fluid). The piston pump is used as, for example, a hydraulic pump mounted in an engine type forklift. A rotary shaft is rotationally supported in the housing of the piston pump. A cylindrical cylinder block is arranged in the housing. The rotary shaft is inserted into the cylinder block. The cylinder block is configured to be rotational integrally with the rotary shaft and has cylinder bores around the rotary shaft. The cylinder bores each accommodates a piston. A shoe is arranged at the end of each piston. The shoes are held by a retainer plate.
A swash plate is accommodated in the housing and has an angle of inclination (an inclination angle) changeable with respect to a direction perpendicular to the rotational axis of the rotary shaft. The surface of the swash plate opposed to the cylinder block is a flat sliding contact surface, on which the shoes slide. As the rotary shaft rotates and the cylinder block rotates integrally with the rotary shaft, the shoes slide on the sliding contact surface of the swash plate. This moves the pistons around the rotary shaft in the circumferential direction of the rotary shaft. Each of the pistons is thus reciprocated in the cylinder bore by the stroke corresponding to the inclination angle of the swash plate as the cylinder block rotates.
The swash plate includes a protrusion as a portion that contacts a control piston, which changes the inclination angle of the swash plate. The protrusion radially protrudes with respect to a section of the sliding contact surface. The housing of the variable displacement swash plate type piston pump has a first housing member and a second housing member both having a tubular shape with a bottom. The first housing member accommodates the cylinder block. The second housing member is coupled to the opening of the first housing member by means of a fastening tool such as bolts. The second housing member has a stopper. The opposite surface of the swash plate from the surface that contacts the control piston of the protrusion comes into contact with the stopper, thus limiting the inclination angle of the swash plate.